1 /* $OpenBSD: mutex.h,v 1.8 2015/07/02 23:01:19 dlg Exp $ */ 2 3 /* 4 * Copyright (c) 2004 Artur Grabowski <art@openbsd.org> 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. The name of the author may not be used to endorse or promote products 14 * derived from this software without specific prior written permission. 15 * 16 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, 17 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY 18 * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL 19 * THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 20 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 21 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; 22 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 23 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR 24 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF 25 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26 */ 27 #ifndef _MACHINE_MUTEX_H_ 28 #define _MACHINE_MUTEX_H_ 29 30 /* 31 * XXX - we don't really need the mtx_lock field, we can use mtx_oldipl 32 * as the lock to save some space. 33 */ 34 struct mutex { 35 volatile int mtx_lock; 36 int mtx_wantipl; 37 int mtx_oldipl; 38 void *mtx_owner; 39 }; 40 41 /* 42 * To prevent lock ordering problems with the kernel lock, we need to 43 * make sure we block all interrupts that can grab the kernel lock. 44 * The simplest way to achieve this is to make sure mutexes always 45 * raise the interrupt priority level to the highest level that has 46 * interrupts that grab the kernel lock. 47 */ 48 #ifdef MULTIPROCESSOR 49 #define __MUTEX_IPL(ipl) \ 50 (((ipl) > IPL_NONE && (ipl) < IPL_TTY) ? IPL_TTY : (ipl)) 51 #else 52 #define __MUTEX_IPL(ipl) (ipl) 53 #endif 54 55 #define MUTEX_INITIALIZER(ipl) { 0, __MUTEX_IPL((ipl)), 0, NULL } 56 57 void __mtx_init(struct mutex *, int); 58 #define mtx_init(mtx, ipl) __mtx_init((mtx), __MUTEX_IPL((ipl))) 59 60 #define MUTEX_ASSERT_LOCKED(mtx) do { \ 61 if ((mtx)->mtx_owner != curcpu()) \ 62 panic("mutex %p not held in %s", (mtx), __func__); \ 63 } while (0) 64 65 #define MUTEX_ASSERT_UNLOCKED(mtx) do { \ 66 if ((mtx)->mtx_owner == curcpu()) \ 67 panic("mutex %p held in %s", (mtx), __func__); \ 68 } while (0) 69 70 #define MUTEX_OLDIPL(mtx) (mtx)->mtx_oldipl 71 72 #endif 73